Langerhans cell histiocytosis masquerading as tuberculosis: a diagnostic dilemma resulting in inappropriate anti-tubercular therapy.

Langerhans cell histiocytosis is known to mimic many other conditions. We present two patients where anti-tubercular therapy was instituted when clinical and radiological features suggested tuberculosis. The correct diagnosis of histiocytosis was reached only on further work-up including immunohistochemistry following un-responsiveness to treatment. In retrospect it was felt that an inordinately high index of suspicion for tuberculosis, clinical and radiological overlap between the two entities, an urgency to start empirical therapy in a rapidly deteriorating patient and pathological similarities between epithelioid histiocytes and pathologic Langerhans cells led to the diagnostic and therapeutic errors. Copyright 2009 Wiley-Liss, Inc.